I have a Cisco DPC3825 DOCSIS 3.0 Gateway modem from my ISP that has 4 lan ports, and I have a second router Linksys WRT54GS (running DDWRT) that has a WAN port and 4 LAN ports + Wireless. This is the general setup of the two routers

Cisco Gateway (192.168.0.1):

Lan1 - Printer 1

Lan2 - Computer 1

Lan3 - Linksys Router (should I use the linksys' Wan or Lan1 port??)

Linksys WRT54GS (192.168.1.1):

Lan2 - Computer 2

Lan3 - Computer 3

WiFi - Laptop

WiFi - Printer 2

I want to be able to access networked folders on computer 2 and 3 from computer 1, and access printer 1 from laptop (on WiFi). So far I have tried connecting Cisco Lan1 -> Linksys Lan1 and disabling DHPC server on the Linksys, and the wired computers (2 and 3) both get great internet speeds and work fine, BUT the WiFi on the Linksys does not work, and I cannot access the Linksys router's control panel from any device. I have also tried connecting Cisco Lan1 -> Linksys WAN port, and now wired computers 2 and 3 can see the control panel, but they get MUCH slower internet speed, and the WiFi still does not work

2 Answers
2

Assuming there's no particular reason for having two separate networks, you could just adjust the IP of the Linksys router to one within the network of the Cisco router. So for example:

Cisco: 192.168.0.1/24

Linksys: 192.168.0.2/24

Then you would just hook up Cisco-LANx to Linksys-LANy, keep DHCP on Linksys disabled, and everything would work fine.

If you actually do have a valid reason for having the two networks, you'd have to configure static routes on each router on how to reach the other network, which additionally would require to actually being able to configure IP addresses for the used ports. Usually, that's not a feature which is present in SOHO routers. You might be able to do that on the WRT with DD-WRT or such, but I'm unsure if the Cisco provides such functionality.